Add problem 3147: Taking Maximum Energy From the Mystic Dungeon

Author: EFanZh

src/lib.rs

@@ -2106,6 +2106,7 @@ pub mod problem_3138_minimum_length_of_anagram_concatenation;
 pub mod problem_3142_check_if_grid_satisfies_conditions;
 pub mod problem_3143_maximum_points_inside_the_square;
 pub mod problem_3146_permutation_difference_between_two_strings;
+pub mod problem_3147_taking_maximum_energy_from_the_mystic_dungeon;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 
 #[cfg(test)]

src/problem_3147_taking_maximum_energy_from_the_mystic_dungeon/mod.rs

@@ -0,0 +1,18 @@
+pub mod suffix_sums;
+
+pub trait Solution {
+    fn maximum_energy(energy: Vec<i32>, k: i32) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [((&[5, 2, -10, -5, 1] as &[_], 3), 3), ((&[-2, -3, -1], 2), -1)];
+
+        for ((energy, k), expected) in test_cases {
+            assert_eq!(S::maximum_energy(energy.to_vec(), k), expected);
+        }
+    }
+}

src/problem_3147_taking_maximum_energy_from_the_mystic_dungeon/suffix_sums.rs

@@ -0,0 +1,41 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::cell::Cell;
+
+impl Solution {
+    pub fn maximum_energy(energy: Vec<i32>, k: i32) -> i32 {
+        let mut energy = energy;
+        let slice = energy.as_mut_slice();
+        let cell_slice = Cell::from_mut(slice).as_slice_of_cells();
+
+        cell_slice
+            .windows(k.cast_unsigned() as usize + 1)
+            .rev()
+            .for_each(|window| {
+                let first = window.first().unwrap();
+                let last = window.last().unwrap();
+
+                first.set(first.get() + last.get());
+            });
+
+        slice.iter().copied().fold(i32::MIN, i32::max)
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn maximum_energy(energy: Vec<i32>, k: i32) -> i32 {
+        Self::maximum_energy(energy, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}